checkout-cache.c

   1 /*
   2  * Check-out files from the "current cache directory"
   3  *
   4  * Copyright (C) 2005 Linus Torvalds
   5  *
   6  * Careful: order of argument flags does matter. For example,
   7  *
   8  *      checkout-cache -a -f file.c
   9  *
  10  * Will first check out all files listed in the cache (but not
  11  * overwrite any old ones), and then force-checkout "file.c" a
  12  * second time (ie that one _will_ overwrite any old contents
  13  * with the same filename).
  14  *
  15  * Also, just doing "checkout-cache" does nothing. You probably
  16  * meant "checkout-cache -a". And if you want to force it, you
  17  * want "checkout-cache -f -a".
  18  *
  19  * Intuitiveness is not the goal here. Repeatability is. The
  20  * reason for the "no arguments means no work" thing is that
  21  * from scripts you are supposed to be able to do things like
  22  *
  23  *      find . -name '*.h' -print0 | xargs -0 checkout-cache -f --
  24  *
  25  * which will force all existing *.h files to be replaced with
  26  * their cached copies. If an empty command line implied "all",
  27  * then this would force-refresh everything in the cache, which
  28  * was not the point.
  29  *
  30  * Oh, and the "--" is just a good idea when you know the rest
  31  * will be filenames. Just so that you wouldn't have a filename
  32  * of "-a" causing problems (not possible in the above example,
  33  * but get used to it in scripting!).
  34  */
  35 #include "cache.h"
  36
  37 static int force = 0, quiet = 0;
  38
  39 static void create_directories(const char *path)
  40 {
  41         int len = strlen(path);
  42         char *buf = malloc(len + 1);
  43         const char *slash = path;
  44
  45         while ((slash = strchr(slash+1, '/')) != NULL) {
  46                 len = slash - path;
  47                 memcpy(buf, path, len);
  48                 buf[len] = 0;
  49                 mkdir(buf, 0755);
  50         }
  51 }
  52
  53 static int create_file(const char *path, unsigned int mode)
  54 {
  55         int fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0600);
  56         if (fd < 0) {
  57                 if (errno == ENOENT) {
  58                         create_directories(path);
  59                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, 0600);
  60                 }
  61         }
  62         if (fd >= 0)
  63                 fchmod(fd, mode);
  64         return fd;
  65 }
  66
  67 static int write_entry(struct cache_entry *ce)
  68 {
  69         int fd;
  70         void *new;
  71         unsigned long size;
  72         long wrote;
  73         char type[20];
  74
  75         new = read_sha1_file(ce->sha1, type, &size);
  76         if (!new || strcmp(type, "blob")) {
  77                 return error("checkout-cache: unable to read sha1 file of %s (%s)",
  78                         ce->name, sha1_to_hex(ce->sha1));
  79         }
  80         fd = create_file(ce->name, ce->st_mode);
  81         if (fd < 0) {
  82                 free(new);
  83                 return error("checkout-cache: unable to create %s (%s)",
  84                         ce->name, strerror(errno));
  85         }
  86         wrote = write(fd, new, size);
  87         close(fd);
  88         free(new);
  89         if (wrote != size)
  90                 return error("checkout-cache: unable to write %s", ce->name);
  91         return 0;
  92 }
  93
  94 static int checkout_entry(struct cache_entry *ce)
  95 {
  96         struct stat st;
  97
  98         if (!stat(ce->name, &st)) {
  99                 unsigned changed = cache_match_stat(ce, &st);
 100                 if (!changed)
 101                         return 0;
 102                 if (!force) {
 103                         if (!quiet)
 104                                 fprintf(stderr, "checkout-cache: %s already exists\n", ce->name);
 105                         return 0;
 106                 }
 107         }
 108         return write_entry(ce);
 109 }
 110
 111 static int checkout_file(const char *name)
 112 {
 113         int pos = cache_name_pos(name, strlen(name));
 114         if (pos < 0) {
 115                 if (!quiet)
 116                         fprintf(stderr, "checkout-cache: %s is not in the cache\n", name);
 117                 return -1;
 118         }
 119         return checkout_entry(active_cache[pos]);
 120 }
 121
 122 static int checkout_all(void)
 123 {
 124         int i;
 125
 126         for (i = 0; i < active_nr ; i++) {
 127                 struct cache_entry *ce = active_cache[i];
 128                 if (checkout_entry(ce) < 0)
 129                         return -1;
 130         }
 131         return 0;
 132 }
 133
 134 int main(int argc, char **argv)
 135 {
 136         int i, force_filename = 0;
 137
 138         if (read_cache() < 0) {
 139                 die("invalid cache");
 140         }
 141
 142         for (i = 1; i < argc; i++) {
 143                 const char *arg = argv[i];
 144                 if (!force_filename) {
 145                         if (!strcmp(arg, "-a")) {
 146                                 checkout_all();
 147                                 continue;
 148                         }
 149                         if (!strcmp(arg, "--")) {
 150                                 force_filename = 1;
 151                                 continue;
 152                         }
 153                         if (!strcmp(arg, "-f")) {
 154                                 force = 1;
 155                                 continue;
 156                         }
 157                         if (!strcmp(arg, "-q")) {
 158                                 quiet = 1;
 159                                 continue;
 160                         }
 161                 }
 162                 checkout_file(arg);
 163         }
 164         return 0;
 165 }